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Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage
BACKGROUND AND AIMS: Differences in local abundance and ploidy level are predicted to impact the direction of introgression between species. Here, we tested these hypotheses on populations of Betula albosinensis (red birch) and Betula platyphylla (white birch) which were thought to differ in ploidy...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6612935/ https://www.ncbi.nlm.nih.gov/pubmed/30916314 http://dx.doi.org/10.1093/aob/mcz024 |
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author | Hu, Ya-Nan Zhao, Lei Buggs, Richard J A Zhang, Xue-Min Li, Jun Wang, Nian |
author_facet | Hu, Ya-Nan Zhao, Lei Buggs, Richard J A Zhang, Xue-Min Li, Jun Wang, Nian |
author_sort | Hu, Ya-Nan |
collection | PubMed |
description | BACKGROUND AND AIMS: Differences in local abundance and ploidy level are predicted to impact the direction of introgression between species. Here, we tested these hypotheses on populations of Betula albosinensis (red birch) and Betula platyphylla (white birch) which were thought to differ in ploidy level, the former being tetraploid and the latter diploid. METHODS: We sampled 391 birch individuals from nine localities in China, and classified them into species based on leaf morphology. Twelve nuclear microsatellite markers were genotyped in each sample, and analysed using principal coordinates analysis and STRUCTURE software. We compared the effects of two different methods of scoring polyploid genotypes on population genetic analyses. We analysed the effect of ploidy, local species abundance and latitude on levels of introgression between the species. KEY RESULTS: Leaf morphology divided our samples into red and white birch, but genetic analyses unexpectedly revealed two groups within red birch, one of which was tetraploid, as expected, but the other of which appeared to have diploid microsatellite genotypes. Five individuals were identified as early-generation hybrids or backcrosses between white birch and red birch and five were identified between red birch and ‘diploid’ red birch. Cline analysis showed that levels of admixture were not significantly correlated with latitude. Estimated genetic differentiation among species was not significantly different between determined tetraploid and undetermined tetraploid genotypes. CONCLUSIONS: Limited hybridization and gene flow have occurred between red birch and white birch. Relative species abundance and ploidy level do not impact the direction of introgression between them, as genetic admixture is roughly symmetrical. We unexpectedly found populations of apparently diploid red birch and this taxon may be a progenitor of allotetraploid red birch populations. Incomplete lineage sorting may explain patterns of genetic admixture between apparently diploid and allotetraploid red birch. |
format | Online Article Text |
id | pubmed-6612935 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-66129352019-07-12 Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage Hu, Ya-Nan Zhao, Lei Buggs, Richard J A Zhang, Xue-Min Li, Jun Wang, Nian Ann Bot Original Articles BACKGROUND AND AIMS: Differences in local abundance and ploidy level are predicted to impact the direction of introgression between species. Here, we tested these hypotheses on populations of Betula albosinensis (red birch) and Betula platyphylla (white birch) which were thought to differ in ploidy level, the former being tetraploid and the latter diploid. METHODS: We sampled 391 birch individuals from nine localities in China, and classified them into species based on leaf morphology. Twelve nuclear microsatellite markers were genotyped in each sample, and analysed using principal coordinates analysis and STRUCTURE software. We compared the effects of two different methods of scoring polyploid genotypes on population genetic analyses. We analysed the effect of ploidy, local species abundance and latitude on levels of introgression between the species. KEY RESULTS: Leaf morphology divided our samples into red and white birch, but genetic analyses unexpectedly revealed two groups within red birch, one of which was tetraploid, as expected, but the other of which appeared to have diploid microsatellite genotypes. Five individuals were identified as early-generation hybrids or backcrosses between white birch and red birch and five were identified between red birch and ‘diploid’ red birch. Cline analysis showed that levels of admixture were not significantly correlated with latitude. Estimated genetic differentiation among species was not significantly different between determined tetraploid and undetermined tetraploid genotypes. CONCLUSIONS: Limited hybridization and gene flow have occurred between red birch and white birch. Relative species abundance and ploidy level do not impact the direction of introgression between them, as genetic admixture is roughly symmetrical. We unexpectedly found populations of apparently diploid red birch and this taxon may be a progenitor of allotetraploid red birch populations. Incomplete lineage sorting may explain patterns of genetic admixture between apparently diploid and allotetraploid red birch. Oxford University Press 2019-07 2019-03-27 /pmc/articles/PMC6612935/ /pubmed/30916314 http://dx.doi.org/10.1093/aob/mcz024 Text en © The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Articles Hu, Ya-Nan Zhao, Lei Buggs, Richard J A Zhang, Xue-Min Li, Jun Wang, Nian Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage |
title | Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage |
title_full | Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage |
title_fullStr | Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage |
title_full_unstemmed | Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage |
title_short | Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage |
title_sort | population structure of betula albosinensis and betula platyphylla: evidence for hybridization and a cryptic lineage |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6612935/ https://www.ncbi.nlm.nih.gov/pubmed/30916314 http://dx.doi.org/10.1093/aob/mcz024 |
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